Ahearn (Eocene of the United States)
Where: Pennington and Shannon County, South Dakota (43.6° N, 102.5° W: paleocoordinates 44.9° N, 93.6° W)
• coordinate based on political unit
When: Ahearn Member (Chadron Formation), Chadronian (37.2 - 33.9 Ma)
Environment/lithology: terrestrial; lithology not reported
Size class: macrofossils
Primary reference: J. Clark and J. R. Beerbower. 1967. Geology, paleoecology, and paleoclimatology of the Chadron Formation. Fieldiana 5(5):21-74 [J. Alroy/J. Alroy/J. Alroy]more details
Purpose of describing collection: paleoecologic analysis
PaleoDB collection 16885: authorized by John Alroy, entered by John Alroy on 18.02.1993, edited by Jonathan Marcot
Creative Commons license: CC BY (attribution)
Taxonomic list
• dated at 36.3 +/- 0.7, 35.1, and 36.2 Ma: Emry et al. 1987; average is 35.87 (= 36.80) Ma
Show authors, comments, and common names
Reptilia | |
Alligator cf. prenasalis Loomis 1904 alligator | |
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"Apalone leucopotamica" = Trionyx leucopotamicus4
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Peltosaurus sp. Cope 1873 squamates | |
Mammalia | |
Hyaenodon cf. horridus Leidy 1853 creodont
Hyaenodon cf. montanus Douglass 1902 creodont | |
? Eusmilus sp. Gervais 1876 false sabre-tooth | |
"Daphoenocyon minor n. sp." = Brachyrhynchocyon dodgei
"Daphoenocyon minor n. sp." = Brachyrhynchocyon dodgei Scott 1898 bear-dog | |
"Parictis dakotensis" = Subparictis dakotensis2
"Parictis dakotensis" = Subparictis dakotensis2 Clark 1936 carnivoran SE 1/4 NE 14 NW 1/4 sec 5 T4S R12E, Pennington Co.; same as type locality of P. gilpini
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Parictis parvus n. sp. Clark and Beerbower 1967 bear from west flank of Quinn Draw, Shannon Co.: see Clark and Guensburg 1972
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Mesohippus celer, "Mesohippus viejensis" = Mesohippus bairdi, "Mesohippus hypostylus" = Mesohippus bairdi
Mesohippus celer Marsh 1874 anchitheriine horse
"Mesohippus viejensis" = Mesohippus bairdi Leidy 1850 anchitheriine horse
"Mesohippus hypostylus" = Mesohippus bairdi Leidy 1850 anchitheriine horse | |
Trigonias sp. Lucas 1900 rhinoceros | |
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Colodon occidentalis Leidy 1868 tapir | |
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Tylopoda indet. even-toed ungulate "camelid new genus and species": may be Montanatylopus; specimens not discussed by Prothero 1986
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Merycoidodon sp. Leidy 1848 oreodont "Big Corral Draw... Pennington Co.:" discussed by Stevens and Stevens 1996
Miniochoerus cf. forsythae8 Schultz and Falkenbach 1968 oreodont one specimen of "Merycoidodon sp."; said to to "probably" be this species
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Archaeotherium cf. coarctatum, Archaeotherium cf. mortoni, "Archaeotherium cf. altidens" = Scaptohyus altidens1
Archaeotherium cf. coarctatum Cope 1889 even-toed ungulate
Archaeotherium cf. mortoni Leidy 1850 even-toed ungulate | |
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Hypertragulidae indet. Cope 1879 ruminant | |
Agriochoerus cf. antiquus Leidy 1850 agriochoerid | |
Ischyromys sp. Leidy 1856 rodent | |
Eomyidae indet. Winge 1887 rodent | |
Amphibia | |
Eopelobates grandis Zweifel 1956 spadefoot toad |